Electric switch lock for railroads



1951 A. LANGDON ELECTRIC SWITCH LOCK FOR RAILROADS 4 Sheets-Sheet 1 Filed Jan. 7, 1946 FIG.4.

- INVENTOR.

H is ATTORNEY Aug. 28, 1951 LANGDQN 2,565,773

ELECTRIC SWITCH LOCK FOR RAILROADS Filed Jan. '7, 1946 4 Sheets-Sheet 2 FIG-.2.

IN VE N TOR.

N am m,

His ATTORNEY Aug. 28, 1951 LANGDQN 2,565,773

ELECTRIC SWITCH LOCK FOR RAILROADS 4 Sheets-sheat s Filed Jan. '7, 1946 s; & s 3 .8 r E o 5 a Q 0 5% g R U- m J l O -J{ (fl/{"14 3 N g a 5; 2 E9. :5

6 1 Q N 1 i a N '0 l E 7 I 1. ,1 m x I 1;

n -J 1 g a 1 i i a 09 A I INVENTOR.

W M m His ATTORNEY Aug. 28, 1951 A, LANGDON 2,565,773

ELECTRIC SWITCH LOCK FOR RAILROADS Filed Jan. 7, 1946 4 Sheets-Sheet 4 IN V EN TOR.

MM 4% WMW His ATTORNEY Patented Aug. 28, 1951 2,565,773 ELECTRIC SWITCH LOOK FOR RAILROADS Andrew Langdon, Brighton,

' General Railway Signal Company,

N. Y., assignor to. Rochester,-

Application Januar v, 1946', SerialNo'. 639.612

11 Claims; 1

This invention relates to a locking device, and it more particularly pertains to" an electric lock for limiting the hand operation of a railway track switch.

It is desirable where certain turnout tracks and outlying track switches connect to main line tracks, to lock such switches against operation under unsafe and unauthorized conditions. If these switches are frequently used they may be power operated, and the electric locking of such switches is contained in themeans for power operation, but if theswitches are not used frequently enough to warrant the expense of a power perated switch mechanism and its control circuits, they may be hand operated with electric lock mechanisms applied to allow hand throw opera tion only when the locks are electrically controlled from some remote point such, for example, as a dispatchers oifice. Such remote control of the electric locks maybe communicated from the dispatchers office by a direct wire control, code communication system, or other communication means, dependent upon the requirements of practice. The lock mechanisms must of course be secured to the railway ties, and therefore they are subject to severe vibrations.

An object of the present invention is to provide an electric lockmechanism that will be reliable in its operation under the most severe-conditions of vibration caused by passage of trains,

and under the most severe conditions of abuse in the manualoperation of the track. switch with which it is associated.

Another object of the present. inventionis to provide emergency release meansin a switchlock by which a trainrnan, upon proper verbal-authorization from a dispatcher or other authorized person, may break a seal and. cause the manual release of theelectric lock to allow the hand'operation of the track switch. Such procedure may be. required upon the failure of the above mentioned remote control'means due to bad weather,

or other conditions adverse to-remote electricalcontrol.

Another object of the present invention is to provide a means for preventing the'operationof. the emergency release on the electric loc'k'by .unauthorized persons. This is accomplished by providing, a mechanical interlock between the catch used for locking'the hand throw lever-in position and an emergency release cover. This arrangement provides that in order to breakthe' seal of the emergency release and release: the electric loc'kmanually, itis first necessary to removethe. padlock from-the catoh used" f orilockingthelhand throw lever in position before the cover over the emergency release lever may be opened. this manner it is possible to prevent unauthorized persons from tampering with the emergency release lever and possibly causing signals to display restrictive indications because of the opening of contacts in the electric lock mechanism. Conversely, it is provided that the padlockcannot be replaced unless the emergency release cover is closed.

Another object of the present invention with respectto the emergency release of the electric lock isto provide a cheek to insure the restoration of the 'sealon the emergency release: lever each time after an emergency release operation of the electric lock'hasbeen required. This object is accomplished by allowing only partial restoration to normal of the electric lock mechanism after the hand throw switch has: been operated and returned to its normal position subsequent to the release of. the electric lock-by-the operation of its emergency release lever. This limited restoration of the lock holds contacts open-in the lock mechanism to prevent the clearing of a signal governing trafiic' over the track switch with which-such lock is associated. 'It-is therefore pro vided' that contacts on the switch lock which are normally closed to control a signal but which are opened by the emergency release means are held open 'until a signal maintainer or other author ized person who has a keyto the cove'r of the switch lock opens such cover and mechanically releases the emergency controlled-means for'holding such contacts open. It is the duty ofesu'ch maintainer or other authorized person to reseal the emergency release lever upon releasing the emergency control mechanism-as describedabove.

Another object of the present" invention with respect tothe emergency release means-is to provide an interlockbetween theemergency release cover and an emergency release lever to provide for automatic restorationof such lever to an intermediate position upon closure of the cover after such emergency'release lever and has been moved to its fully operated position for unlock-- ing the catch. Such arrangement provides that the emergency release lever must be moved toa position toallow' theelectric lock" tob e actuatedto itslock-ing' position before the emergency re-- lease cover can be closed. Therefore before thepadlock can be reinserted to lock the'catch in its normal position theemergency release cover must be closed,- because-the catch' cannot b'e'ful ly resorted to its normal position unless the emergency releas'e cover- 'iscl'ose'di Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which like reference characters are used to designate corresponding parts throughout the several views, and in which:

Fig. 1 shows a typical switch layout having a hand operated switch stand with its hand op-- eration limited by an electric lock mechanismas provided by the present invention;

Fig. 2 is an end view of the electric switch lock with certain parts shown in cross-section, such section being taken along the line 2-2 of Fig. 1,

and also along the line 2--2 of Fig. 3;

Fig. 3 is a side view of the electric switch lock with certain parts shown in cross-section, such sectional view being taken along the line 33 of Fig. 2;

Fig. 4 is an end view of a portion of the switch lock particularly showing the emergency release cover;

Fig. 5 is a sectional side view taken along the line 5-5 of Fig. 3 showing more particularly the relationship of the catch release cam to the latch and lock members with which its operation is associated;

Fig. 6 is a plan view of the part of the operating mechanism of the switch lock more particularly associated with the operation of the contacts, such view being a section taken along the line '6 6 of Fig. 3; and

Fig. 7 is a sectional view of a part of the emergency release lever and-cover taken along the line 'I.'! of Fig. 4.

With reference to Fig. 1, the general organization of the switch control apparatus is shown in which the track switch W is positioned by a throw rod 2 connecting the switch points 3 and 4 with the hand throw operating mechanism HT. The operation of the hand throw mechanism is provided by athrow bar 5, such bar being held in its normal position under normal conditions by the electric lock EL. The padlock P further secures the track switch against unauthorized operation by locking the catch 6 of the electric lock in its normal position. When the switch is operated, the hand throw bar 5 assumes the reverse position as indicated by dotted lines I. Inasmuch as the hand throw mechanism HT may be of any suitable type, it is believed that description of such mechanism in detail will be unnecessary as such types of mechanisms are well known to those skilled in the art.

The hand throw bar 5 is normally held in its position as shown in Fig. 1 by the catch 6, and such catch is restricted in its operation by the detent 8 which is locked in a position by the padlock P to engage the catch 6 under normal conditions.

With reference to Fig. 2 the catch 6 is pivoted at the bar. 9, and secured by the set screw It to such bar. Extending from the lower portion of the catch 6 is a forked member II for engaging the pin I2of the nut I3 of the catch release rod CR. Such rod is disposed to operate longitudinally through the main case I4 of the electric lock at the point I5 and through the catch release case I6 at the point I! to cause the operation of the catch release cam I8 which has a forked portion at its end I 9 operated by the pivot 26 of the stud 2I of the catch release rod CR.

Upon the operation of the switch lock catch 6, the rotation of the catch release cam I8 is effective to operate the latch member 22 (see Fig. 5) to close contact 23 (see Fig. 6) for the energization of the electric magnet M. The movement of the catch release cam I8 is limited by the lock member 24 unless such lock member has been operated electrically to clear the detent 25 of-the catch release cam I B to allow the completion of the operation of the electric lock mechanism to its unlocked position. The lock member 24 includes a leaf spring 9| for reducing to a minimum the transmission of shock to the armature of the magnet, if an attempt is made to operate the switch before the magnet is energized; and it also includes a bumper 92 for absorbing shock under such conditions when the lock member 24'is pressed against the stationary stop 93 which is a part of the case I4.

To consider more specifically the construction to provide the above described mode of operation, with reference to Fig. 2, the catch 6 is formed with a treadle 26 at its base, and it is normally held in its locking position by the detent 8 whichthe catch release cam I8 to operate the latchmember (see Figs. 5 and 6). The structure of the catch release rod CR to provide such mode of operation is provided by the rod comprising a stud 2I and nut I3 assembly which provides an arrangement by which the bushings 30 and 3| and the spring 29 can be assembled on the stud 2| within the spring compartment formed by the lower part of the switch lock case I4 in combination with the case I6 of the catch mechanism.

The bushings 30 and 3| are arranged to be movable along the shank 32 of the stud 2I within the limits of the shoulder 33 of the stud 2| and the shoulder 34 of the nut I3, respectively. The bushings 30 and 3| are large enough in diameter to be restricted at the points I5 and ll of the casings I and I6 respectively, and thus provide a spring bias for the catch release rod to a center position. It will be noted that the position of the catch release rod as shown is in its normal position, and that the spring 29 is under tension to bias the catch release rod to its center position upon release of the catch member 6 by the detent B. It will also be noted that the shoulder 34 of the nut I3 is so spaced with respect to the overall longitudinal movement of the catch release rod CR that it will cause compression of the spring 29 when the rod is moved beyond the position at which it is restricted by the lock member 24. This being the case, the catch member 6 is spring actuated from its full normal and its full released positions toa center position when it is mechanically disengaged from such extreme position.

In actual operation of the lock mechanism EL, the lifting of the throw bar 5 out of its normal position, with the catch 6 held down by the trainman applying pressure to the treadle 26 causes the bar 35 (see Fig. l) tobe moved under'the catch member 6 through the opening 36in the casing I3 (see Fig. 2) and thereby hold. such ,catch in its released position throughout;

assume the remainder of the operation of the track switch; It will be noted; withreferenceto'Fig;1-,

that the crank 31" on the handthrow' mechanism- I-IT operates the bar 35-longitudinally un-der the catch 6 whenever the hand throw lever is in:

any position other than itsfulf normalposition.-

With reference to Fig. 3-, the catch release caml8 has a shaft 38 extending longitudinally beposition unless the locking member 24 1s raised to provide clearance for the-detent-a Withreference to Fig-t 6, the latch: member 22- is pivoted at the pin =and has normally" closed and normally opencontacts such as contacts 46- and 23 respectivelysecured thereto.

In asimilar manner the l'ockmember 24 is pivoted at the pin 45- andsuch member has normally open and normally'clo'sed contacts 41 and 43 respectively secured thereto by screws 49 and 50. With reference to Fig 3-,.it-w-ill' benoted that the lock member 24 includes an armature 5| which is attracted by the energization'of. the magnet M, and therefore-the energization of. the magnet M is eilfectivev to cause-thelocl: member 24: to rotate about the pivot. pointz45. and: to raise.

the end of the member 24 sufficiently: to: allow clearance for. the detent 255 (see. Fig.6 of the catch release cam 6.

In order to insure. that the latch and lock members 22 and 24 respectively will remain in.

their normal positions irrespective; of. severe'conditions of vibration, a relatively stiff spring 52. is provided to bias the latch member; toits; normal position, and the latch member 22 is effective. to held the lock member 24- in itsnormal positionbecause of the shoulder 53 formed. at-the left of the latch member 22 extending. above the lock member 24 to force such member into its locking position. The relatively light. effective to hold the lockmember 24.- in looking, engagement when the latch member 22 is operated until such lock member is electrically actuated to a release position.

As a means for providing, suitable. connections to the contacts of both the latchand. lockmembers 22 and 24 respectively, a terminal'block 55 is secured at the top of the electric lock mechanism so that the terminals will be readily accessible when the cover is removed. Such block also provides support for the stationary part of the contacts. Along the side of the terminal block is a lamp receptacle 55'- f'o'r'the' lamp 51'. Such lamp is illuminated whenever the electric lock is energized to indicate to the trainman through the translucent insert 58 in the cover 59 when the switch can be operated;

To consider the manner in which the electric lock mechanism is controlled electrically, the raising of the latch member 22- to it'scperated position by the cam 18 is effective to close contact 23 (seee Fig. 6) of such member and thereby close the local portion of the circuitfor the energization of the magnet M, energy beingapplied from a remote point to the wire 81-, through contact 23, and the two coils ofthe magnet M connected in series to the-opposite po'tential of thei the dotted line at 43 spring 54 is source of energy as applied to the wire 82-. accordance with the energization ofthe coils of the electromagnet M the attraction of the arma-- tur'e 5| of the mechanism causes the lock member 24 to be raised to allow clearance for'the catch release cam detent 25 (see Fig. 5). In such operation, an obvious circuit is closed at contact 41 (see Fig. 6) to cause the energization of the lamp 5'5 to indicate to the trainman that the release of the electric lock has become effective.

It will be noted thatv normally closed contacts: onboth. the latch member 22 and the lock member 24 are normally effective to close a portion "of a signal control circuit. That is, with reference to Fig. 6, a portion of a signal control circuit has been illustrated which extends through contacts 45. and as. of lock member 24 and latch member 22- respectively to provide that the signal thus con trolled. can be cleared only if the latch and 1001': members are both in their normal positions.

With reference to Figs. 3 and 4, an emergency release lever til is secured at one end by a screw (Szl to a pin 52 extending through the case [4- of the electric lock, such pin being secured inside the. case to an emergency release cam 63 havingan. angular surface 64 at the end for the engagement of the latch member 22 and the lock member 24 when the emergency release lever is opre; i I

erated.

The emergency release lever 88 is normally in the position shown in Fig. 4 with its end 65' ad jac'ent the stationary post 66, and a seal 61 ex tending through registration holes provided" for that purpose in these respective parts. i

With reference to Fig. 3, the cap 68 is provided for covering the emergency release lever and its seal El. Such cap is pivoted at the pin 69 and formed with a circular detent I8 about the radius of such pin for engaging the pin l! which extends" through the side of the case [4. The pin H is biased to a position in engagement of the detect it. of the emergency release cover 68 by the spring '52 acting against the shoulder 98. By this arrangement, it is provided that the opening of. the emergency release cover 68 can be effected only if the pin H can be free to travel longitu-- din'ally to the left. Such movement of the pin is normally restricted by the boss 13 on the side of the catch release cam l8 but, with reference to Fig. 5, an elongated hole 74 is provided in the catch release cam is to allow clearance for such pin as the cam is operated to an initiating post-- tion. In other words, in order to open the emergency release cover 68, it is first necessary toremove the padlock P, which secures the catch member 5 in its normal position, and remove the length of the elongated hole is such as to allow the complete operation of the mechanism to a fully unlocked position. With reference to Figs. 3 and 4, the pivot pin 59 for the emergency release cover is held in position by a bracket '55 secured to the case M- by screws 76. Such bracket provides a housing around the detent 15. It is illustrated in'Fig. 4';

that thecover 6E and the detent ls-are secured to the pivot pin 69 by rivets or. other suitable meansat points T8: It will be noted that'th placed as to strike the lever 60 spring 121's not only effective to bias the pin II to its normal position to be in disengagement with the catch release cam I8, but such spring is also eifective to hold the cover 68 tightly-closed upon the cover gasket 19. It will also be noted that the operation of the pin H by the circular detent is such that the bias of the spring 12 is applied to the cover until it is opened far enough so that the point 80 of the detent slips past the end of the pin 1 I. ing of the cover, the spring is relatively ineffective to cause the closing of the cover, and such cover will remain open in its fully opened position.

After considering the structure particularly related to the emergency release of the electric lock, consideration can now be given to the mode of operation of the electric look under emergency release conditions. To initiate such emergency release, the trainman must first remove the padlock P from the detent 8, and release the detent 8 from the catch 6. The spring 29 is then effective to bias the catch release rod to its center position and thereby cause the catch release cam I8 to be operated to a position to allow'the longitudinal movement of the pin H and thus allow the opening of the emergency release cover 68. The breaking of the seal 6! inside the cover then allows the lever 60 to be operated to cause the emergency release cam l8 to operate both the latch member 22 and the lock member 24 to their operated positions. The raising of the lock member 24 to its operated position allows clearance for the detent 25 on the catch release cam l8, and therefore the trainman can complete the release of the catch 6 by applying pressure to the treadle 26, thus allowing the hand operation of the switch throw bar 5.

When the switch is again restored after it has been'operated under emergency release conditions, the complete restoration of the catch 6 to its normal position for the engagement of such catch by the detent 8, is restricted by the pin H if the emergency release cover 68 is still open because of such pin havingbeen operated longitudinally within the elongated hole 74 of the catch release cam I8. Thus, it is required that the emergency release cover '68 be closed before the holes in the detent 8 and the case [6 can be aligned for receiving the padlock P.

It is further provided that the emergency release cover 68 cannot be closed to release the catch release cam l8 if the emergency release lever 60 is left in its fully operated position so as to hold the locking member 24 in its operated position. Such interlock is provided by the pin 83 in the emergency release cover 68 which is so and restrict the closing of the cover if the emergency release lever 60 is in its fully operated position.

It is further provided, with reference to Fig. 7, that the closure of the emergency release cover 68 is effective to automatically operate the emergency release caln 63 to cause such cam to release the locking member 24, and allow such member to be restored to its normal position. This mode of operation is accomplished by the provision of the bevel 86 provided on the end of the pin 83, and the bevel 94 provided on the emergency release lever 60. It will be readily apparent that from this arangement, the closure of the cover 68 is automatically effective to operate the emergency release lever 60 to a position to cause the detent 84 of the emergency release cam 63 to assume a position between the locking member Beyond this point in the open- 24 and the latch member 22, such cam being restricted in its restoration to a full normal position the latch contact 46 (see Fig. 6) is not restored to its normal position to close the signal control circuit after the lock mechanism has been released by emergency operation. This mode of operation is provided by the detent 84 at the top of the emergency release cam 63 as shown in Fig. 4. In the operation of the emergency release lever 60, the detent 84 is moved past the point 85 at the end of the latch member 22, and upon the restoration of the emergency release lever following the desired operation of the track switch, the lever 613' can only be restored to a position in which the detent 84 will engage the latch member 22 at the point 85 and thereby cause the signal contact 46 of such latch member to be maintained open. It will be noted with reference to Fig. 6 that the lateral spacing between the end of the lock member 24 and the end of the latch member 22 is such as to allow the detent 84 tobe retained between such members and yet allow the lock member 24 to be restored to its normal locking position. By this arrangement it is required that the maintainer, or some other authorized person be called to unlock the padlock P2 (see Fig. 3) and open the cover 59 of the electric lock mechanism and then manually release the emergency release cam 63 by lifting the latch member and operating the emergency release lever 60 to its full normal position. In this manner it is called to the attention of such anthorized person that the seal has been broken and it is his duty to replace the seal at that time. With reference to Figs. 4 and 7 the seal 6'! is placed through a hole 88 in the post 66 when in registration with a hole in the pin 89 which is secured to the mergency release lever 60.

Having thus described an electric lock mecha= nism as one embodiment of the present invention, it is desired to be understood that this form is selected to facilitate in the disclosure of the invention rather than to limit the number of forms which the invention may assume, and it is to be further understood that various adaptations, alterations and modifications may be applied to the specific form shown to meet the requirements of practice without in any manner departing from the spirit or scope of the present invention except as limited by the appending claims.

What I claim is:

1. In an electric lock for hand operated track switches, a manual lever having normal and reverse positions for operating the points of a track switch, a catch having a normal position for locking said manual lever in a particular one of said positions, such catch being normally secured by a padlock in said normal position, a lock member for governing the release of said catch, manual emergency release means having normal and operated positions for allowing said lock member-to release saidv catch when in its operated position; an; emergency release cover efiective g'ency release means secured by a seal in when closed to prevent themanual operation :of

said emergency release means to said operated verse positions, a catch having a normal position .for locking'saidman-ual lever in a particular one of its positions, .a padlock, means for locking said catch in said normal position by the insertion of said padlock, alocking member forgoverning the release of said catch, manually operable emera normal position but having an operated position for operating said locking member to allow the release of said catch, a cover effective when closed to prevent the manual operationof said emergency release means and the breaking-of-said seal, and means for allowing the opening of said cover only when said padlock is removed from said, catch.

3. In an electric lock of the character described for a manual switch lever having normal and reverse positions, a catch having a normal position for locking said manual .lev'erin a particular one of said positions, a locking member for governing the release of said catch, manually operable emergency release :means effective when operated for rendering said locking member effective to release said catchya cover effective when closed to prevent the manual operation of said emergency release means, locking means for securing said catch in said :normal position by a padlock, and means controlled by said looking member for allowing said cover to he opened only when said catch is notrs'ecured :by said padlock, such means being effective to allow the restoration of said padlock after the operation of said manual switch lever only if said cover is in said closed position.

4. In an electric lock for railroad track switches having a manually operable lever for moving the switch points, a catch effective to restrain said lever from manual operation except when said catch is released, an electromagnet at times acting to release said catch, a manually operable emergency release means effective when operated to release said catch regardless of said electromagnet, a cover effective to prevent access to said emergency release means unless it is opened, means connected to said cover for co-acting with said emergency release means for restoring it to a non-catch-releasing position when said cover is closed, and means for at times lockin said cover in a closed position.

5. In an electric lock for a hand operated track switch, a manual lever having normal and reverse positions for operating the points of said track switch, a catch for locking said lever in a particular position, a lock member for governin the release of said catch, manual operable emergency release means having normal and operated positions effective when operated to allow said lock member to release said catch, a cover for said emergency release means effective when closed to prevent the manual operation of said emergency release means, and means for preventing the closure of said cover when said emergency release means is in said operated position.

6. In an electric lock of the character described for the locking of a manual switch operating lever in a particular position, a catch position,

for locking said manual lever in said particular a locking member for governing the release of said catch, manually operable emergency release means effective when operated for rendering said lock member effective to release said catch, a cover effective when closed to prevent the manual operationof said emergency release means, and locking means for securing said catch in said normal position by a padlock, such means being effective to receive said padlock only when said manually operable emergency release means is ineffective for allowing said lock member to release said catch.

7. In an electric lock having a hand operated track switch, a manual lever having normal and reverse positions for operating said track switch, a padlock, a catch for locking said lever in a particular one of said positions :such, catch being locked in its normal position by said padlock, a lock member for governing the release of said catch, manually operable emergency release means having normal, intermediate and operated positions and effective when moved to its operated position to, allow said lock member to release said catch, a cover effective when closed to prevent the manual operation of said emergency release means, means for allowing the manual restoration of said emergency release means only to said intermediate position from said operated position, and means for locking saidcover in its closed position in accordance with the locking of said catch by said padlock.

8. In an electric lock of the character described for the locking of a manual switch operating lever in a particular position, a catch for locking said lever in said particular position, a lock member for governing the release of said catch, manually operable emergency release means having normal, intermediate, and, operated positions effective when operated to allow said lock member to release said catch, a cover for said emergency release means effective when closed to prevent the manual operation of said emergency release means, means attached to said cover and acting upon the closure of said cover for causing said emergencyrelease means to be restored from said operated position to said intermediate position, and contact means for allowing the clearing of a signal only when said manually operable emergency release means is in said normal position.

9. In an electric lock for railroad switches having a manually operable lever for moving the switch points, a catch having normal, half-normal, and released positions, said catch acting in its normal and half-normal positions to prevent operation of said lever but acting in its released position to permit free movement of said lever, an electric lock permitting movement of said catch between its normal and half-normal positions but preventing its movement between its half-normal and released positions except when such lock is energized, an emergency release means effective when manually operated to release said catch for operation to its released position, a cover preventing manual operation or" said release means when said cover is in. a closed position, means effective to prevent the opening of said cover while said catch is in its normal position, and means for at times locking said catch in its normal position, whereby said emergency release means cannot be operated unless said. catch is unlocked and moved to its half-normal position.

10. In an electric lock for railroad track :switches having a manually operable lever for moving the switch points, a catch being biased to an intermediate position from either a normal or an operated position, said catch being efiective in either its normal or intermediate positions to prevent the operation of said manually operable lever but being efiective in its operated position to permit the free movement of said lever, an electromagnet having a lock member preventing movement of said catch from its intermediate position to its operated position except when said electromagnet is energized, an emergency releaselever effective when manually tions and by said catch in its biased intermediate position for opening a signal circuit, and'a padlock for normally locking said catch in its normal position, whereby said contact means is operated on the removal of said padlock and is maintained operated by said emergency lever in its intermediate position.

11. In an electric lock for railroad track switches having a manually operable lever for moving the switch points, a catch being biased to an intermediate position from both normal and operated positions to which it may at times be manually operated, said catch acting in its normal and intermediate positions to restrain said manually operable lever against manual operation but acting in its operated position to permit the free movement of said lever, an electromagnet having a lock member preventing movement of said catch from its intermediate position to its operated position except when said electromagnet is energized, an emergency release lever having normal, intermediate, and

releasing positions, said emergency lever being effective in its releasing position to act on said lock member of said electromagnet so as to release said catch for movement to an operated position, said emergency lever bein restrained in its intermediate position by an auxiliary catch from restoration to its normal position after having once been operated to a releasing position, a cover member preventing access to said emergency lever except when said cover is in an open position, said cover member also having means requiring operation of said emergency lever away from its releasing position when said cover member is closed, mechanical interlocking means preventing the opening of said cover member while said catch is in itsfnorma'l'position and in turn preventing operation of said catch to its normal position'unless saidcover member is closed, contact means operated by said emergency lever in its intermediateor releasing positions and by said catch in its intermediate and operated positions foropening a signal circuit, a padlock for locking'said catch in its normal position, and other means including another padlock for allowing manual operation of said auxiliary catch to permit the return of said emergency lever to its normal position only by an authorized person, whereby said contact means can only be operated to open the signal circuit when said padlock is removed allowing said catch to assume an intermediate position, but said contact means bein maintained operated to hold the signal circuits open when said emergency lever has been operated until said another padlock has been removed and said auxiliary catch has been released to allow the restoration of' said emergency lever to its normal position.

ANDREW LANGDON.

REFERENCES CITED 7 The following references are of record in the file of this patent:

- UNITED STATES PATENTS 

